"It's just my helmet," the second-round pick from Georgia said. "It's just a little bigger."

His game seems oversized as well.

While the accuracy of Chubb's nickname is up for debate amongst his teammates, one thing that is for sure is that Chubb has made an immediate impact on the Browns and Cleveland's coaches in more ways than one.

Certainly, there's his physical prowess on the field. Linebacker Christian Kirksey called the rookie a "work horse." Carlos Hyde, another of the new backs on Cleveland's roster, called the 225-pounder a "beast" and both said he has the ability to make a defender miss after making just one cut.

But along with his physical abilities, Chubb, selected with the No. 35 pick in this year's draft, has also impressed with his willingness to master the mental side of the game in a way that most first-year players don't always understand.

"I don't really feel like he's a rookie," Hyde said. "Usually, rookies come in and be all kind of lost, just trying to feel their way out. I think Nick understands what's going on. He understands what being a pro is, and he's definitely been on top of the playbook, been on top of his game, so he's been doing a pretty good job."

Early on, Chubb is at the very least giving the Browns, looking to shake off a 0-16 season, options. Coach Hue Jackson said that given the makeup of the team, he believes the Browns will be able to run the ball more than in the previous two years. It's possible that Jackson will use a three-headed attack with Johnson, Hyde and Chubb sharing the workload.

Chubb is no stranger to a rotation system — it's something he did last season with the Bulldogs as he shared playing time and carries with former teammate Sonny Michel, now a rookie with the New England Patriots. Chubb said the two divided the workload play by play or series by series, and played every game together.

In the process, both players racked up big yards. Chubb rushed for 1,345 yards and 15 touchdowns in 2017 while Michele went for 1,227 yards and 16 TDs. Ultimately, it was a system that helped catapult the Bulldogs to the national title game.

It also bonded Chubb and Michel.

"Me and Sony are very good friends," Chubb said. "We both had success. We both got drafted fairly high. To do that with someone who you started in college with, and lived with four years and did everything with, I don't think it could get any better than that."

The Browns hope it can.

If they decide to rotate backs, Chubb is confident they can find success.

"Good competition brings more out of you," he said. "I look forward to competing with these guys and learning from them and eventually playing with and winning some games with them."

Chubb has shown the Browns plenty so far, and Jackson believes there's still a lot of potential in his game.

"Old School" has more to offer than a catchy nickname.

"I think there's a lot to him, more so than what people think," Jackson said. "He just looks like the guy that comes downhill, and here we go. But he has some versatility to him as well. There's some instincts, real runners' instincts that I see. I think he's a really talented runner.